TOKYO, July 30 (Reuters) - Reigning World champion Jiri Prskavec from the Czech Republic finished first In the men"s kayak slalom semifinal on Friday, setting up a contest for gold with Germany"s Hannes Aigner in the final later in the day. Prskavec took bronze in Rio de Janeiro five years ago, with Aigner winning the bronze in London in 2012. The men shot down the white water course in Tokyo as storm clouds gathered nearby. The closest to Prskavec"s time was France"s Boris Neveu, a veteran kayaker who won the world championships in 2014, and American Michal Smolen, who was Pan American champion in 2017. Among the ten paddlers eliminated were Slovenia"s Peter Kauzer, the silver medalist in Rio, who at 37 years old was the oldest competitor in the men"s slalom, and Italy"s Giovanni de Gennaro, who finished second in the heats on Wednesday.